The present invention relates to apparatuses and methods for producing coil members. More specifically the present invention relates to an apparatus and a method for forming coil members of dynamo electric machines by bending electric conductors.
The coil members can be used in stators of electric motors or electric generators. Solutions in this field have been described in PCT Application WO having publication number WO 2012/156066.
The coil members formed with the present invention can have a fork like shape, or other shapes, for example an undulated configuration. Normally, the electric conductor has a relatively large cross section that allows the formed coil member to be self-supporting, i.e. the shape of the coil member is permanently formed according to a specific geometric configuration, which does not change until considerable bending forces are applied. The coil members having the fork like shape are commonly called “hairpins”. A further shape, like the undulated configuration, is described in European publication EP 1372242.
A typical processing sequence involving formed hairpins can foresee: insertion of specific hairpins in respective slots of the core of the dynamoelectric machine, bending end portions of the hairpins that extend beyond an end of the core of the dynamoelectric machine, welding together predetermined ends of the hairpin that have become adjacent as a result of the previous bending operation. PCT Application having publication number WO 2012/119691 describes operations of this type and solutions for accurate alignment of ends of the hairpins that need to be welded together.
Bending to form a coil member requires repetitive steps of feeding predetermined lengths of an electric conductor in alignment with a bending tool, like is described in the above mentioned PCT Application WO having publication number 2012/156066. During the feeding steps, a bending tool engages the electric conductor and performs predetermined movements to cause permanent bending into a required shape of the electric conductor.
A cutting operation is performed to free a formed coil member from the rest of the electric conductor, so that the latter can be successively fed to form further coil members. Operations according to these principles have been described in the above mentioned PCT Application having publication number WO2012/156066.